U.S. Pat. No. 2,813,908 has already disclosed the hydration of olefines on sulpho-containing styrene/divinylbenzene polymers. U.S. Pat. No. 3,257,469 has disclosed specifically the preparation of TAA on such acid sulpho-containing ion exchangers by the reaction of i-amylene with a molar excess of water. This reaction is carried out, for example, at a pressure of 35 bar and temperatures of 66-107.degree. C. An industrially sufficient proportion of TAA in the reaction product is achieved by additionally using solvents, of which i-propanol and acetone are mentioned in particular. Thus, this process necessarily comprises the removal of the additionally used solvent from the reaction mixture.
U.S. Pat. No. 4,182,920 represents a further development of the process described last and is likewise directed to the preparation of TAA. The fact which is pointed out as novel is that the entire starting mixture forms only one homogeneous phase and a portion of the i-amylene is fed into a second of a total of at least two reactors. The solvent mentioned specifically is acetone, which, according to the working examples, is present in an amount of 60-75% by weight of the total feed stream. This process is likewise carried out using excess molar amounts of water of hydration.
Furthermore, it is a generally known that the hydration of i-butene results in high amounts of tert.-butanol in the reaction mixture, whereas on conversion of i-amylenes substantially lower amounts of TAA are formed in (he reaction mixture due to the unfavourable position of equilibrium.